Why SEM is the most suitable method for fiber analysis

Fibers are all around us. Different types of fibers exist, but in most cases we do not notice them because they are used in a product. In case an object is much longer as it is wide we consider it a fiber. Fibers have specific properties for the product in which they are used. This blog will describe the different ways these fibers can be classified and how their performance can best be analysed. Hint: it has something to do with putting fibers under a specific type of microscope. You're about to discover the most suitable method for fiber analysis, so do read on!

Microscopic identification and classification of fibers

If you search for the word fiber online you will see that fibers can be classified as natural fibers or as engineered fibers. In this article, we e will focus on the engineered fabrics and in particular on the non-wovens.

Non-woven fibers;

Are engineered fabrics

Have a targeted structure and targeted properties

Are manufactured by high speed and low-cost processes

Are based on the technologies of the creation of textiles, papers, and plastics.

Diapers, napkins, air filters, hydraulic filters, construction products etc. are some examples of products containing non-wovens. The fibers in these products are called nanofibers as they can have a diameter < 1µm. Why are they so small? Because you can create higher efficiency products for better air filtration, water absorption, lifetime improvement, etc.

Key in this process is to understand the properties of non-wovens to be able to optimize the output.

Changing the structure of non-wovens requires fiber analysis equipment to examine or test the material’s properties. This can be:

Chemical analysis - emission-, absorption spectrometry, XRF, XPS

Mechanical testing – tensile, abrasion, puncture

Microscopy – optical, electron optical (SEM), AFM.

Microscopy techniques are imperative to evaluating the performance of a filter, for instance. There are different methods to get a microscopic view of fibers. Optical inspection has been the industry standard for the last decades. However, optical inspection has become insufficient for many new applications because fiber dimensions are below the resolution limit of an optical microscope.

Electron microscopy techniques for fiber analysis

Atomic force microscopy is a technique that can be used in the micron range, but it is a very slow process and can cause physical probe issues.

So what's the best microscopic view of fibers one can obtain? We suggest you look into scanning electron microscopy (SEM):

The best microscopy view of fibers: scanning electron microscopy (SEM)

With a higher depth of field and greater image contrast, scanning electron microscopy (SEM) is becoming the new standard for characterizing filtration materials. An SEM image affords a quick and high-resolution visualization of filter media. Elemental analysis, via energy dispersive X-ray spectroscopy (EDS) with SEM, allows for the identification of elements in the fibers or particulates.

About the author

Karl Kersten is head of the Application team at Thermo Fisher Scientific, the world leader in serving science. He is passionate about the Thermo Fisher Scientific product and likes converting customer requirements into product or feature specifications so customers can achieve their goals.